Antenna device and electronic apparatus including antenna device

Abstract

According to one embodiment, an antenna device according to this embodiment includes an antenna ground portion and first and second antenna units. The first antenna unit includes a first feed point, a first feed element connected to the first feed point, and a first parasitic element which operates upon electrically coupling to the first feed element. The second antenna unit includes a second feed point, a second feed element connected to the second feed point, and a second parasitic element which operates upon electrically coupling to the first parasitic element and the second feed element.

What is claimed is: 
     
         1 . An antenna device comprising:
 an antenna ground portion disposed substantially parallel to a ground portion of an electronic apparatus and connected to the ground portion via a ground element; and   a first antenna unit and a second antenna unit which are disposed close to each other within a predetermined distance along a side of the antenna ground portion and for which substantially equal frequency bands for transmission or reception are set,   wherein the first antenna unit comprises   a first feed point disposed close to the side of the antenna ground portion,   a first feed element having an intermediate portion bent at least once, one end portion connected to the first feed point, and the other end portion open, and   a first parasitic element which has one end portion connected to the antenna ground portion and the other end portion open, and operates upon electrically coupling to the first feed element, and   the second antenna unit comprises   a second feed point disposed away from the first feed point at a position near the side of the antenna ground portion,   a second feed element having an intermediate portion bent at least once, one end portion connected to the second feed point, and the other end portion open, and   a second parasitic element which has one end portion connected to the antenna ground portion and the other end portion open, operates upon electrically coupling to the second feed element, and also operates upon electrically coupling to the first parasitic element.   
     
     
         2 . The device of  claim 1 , wherein a distance between a ground position of the first parasitic element and a ground position of the second parasitic element is set to substantially not more than 1/20 a wavelength corresponding to the frequency band. 
     
     
         3 . The device of  claim 1 , wherein a length from a distal end of the first parasitic element to a distal end of the second parasitic element through a side of the antenna ground portion is set to substantially ½ a wavelength corresponding to the frequency band. 
     
     
         4 . The device of  claim 1 , wherein at least one of the first feed element and the second feed element is formed into a T-shape. 
     
     
         5 . The device of  claim 1 , wherein at least one of the first antenna unit and the second antenna unit further comprises one of third parasitic element and a fourth parasitic element which operates upon current-coupling to one of the first feed element and the second feed element at a position opposite to one of the first parasitic element and the second parasitic element through one of the first feed element and the second feed element. 
     
     
         6 . The device of  claim 1 , wherein a length from one of the first feed point and the second feed point to the ground element through a side of the antenna ground portion is set to substantially ¼ a wavelength corresponding to the frequency band. 
     
     
         7 . An electronic apparatus comprising:
 a ground portion; and   an antenna device;   the antenna device comprises   an antenna ground portion disposed substantially parallel to a ground portion of an electronic apparatus and connected to the ground portion via a ground element, and   a first antenna unit and a second antenna unit which are disposed close to each other within a predetermined distance along a side of the antenna ground portion and for which substantially equal frequency bands for transmission or reception are set,   the first antenna unit comprises   a first feed point disposed close to the side of the antenna ground portion,   a first feed element having an intermediate portion bent at least once, one end portion connected to the first feed point, and the other end portion open, and   a first parasitic element which has one end portion connected to the antenna ground portion and the other end portion open, and operates upon electrically coupling to the first feed element, and   the second antenna unit comprises   a second feed point disposed away from the first feed point at a position near the side of the antenna ground portion,   a second feed element having an intermediate portion bent at least once, one end portion connected to the second feed point, and the other end portion open, and   a second parasitic element which has one end portion connected to the antenna ground portion and the other end portion open, operates upon electrically coupling to the second feed element, and also operates upon electrically coupling to the first parasitic element.   
     
     
         8 . The apparatus of  claim 7 , wherein a distance between a ground position of the first parasitic element and a ground position of the second parasitic element is set to substantially not more than 1/20 a wavelength corresponding to the frequency band. 
     
     
         9 . The apparatus of  claim 7 , wherein a length from a distal end of the first parasitic element to a distal end of the second parasitic element through a side of the antenna ground portion is set to substantially ½ a wavelength corresponding to the frequency band. 
     
     
         10 . The apparatus of  claim 7 , wherein at least one of the first feed element and the second feed element is formed into a T-shape. 
     
     
         11 . The apparatus of  claim 7 , wherein at least one of the first antenna unit and the second antenna unit further comprises one of third parasitic element and a fourth parasitic element which operates upon current-coupling to one of the first feed element and the second feed element at a position opposite to one of the first parasitic element and the second parasitic element through one of the first feed element and the second feed element. 
     
     
         12 . The apparatus of  claim 7 , wherein a length from one of the first feed point and the second feed point to the ground element through a side of the antenna ground portion is set to substantially ¼ a wavelength corresponding to the frequency band.